Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba$_{0.4}$K$_{0.6}$Fe$_2$As$_2$

Fuente: arXiv
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Autori principali: Li, Yang, Wu, Dingsong, Shu, Yingjie, Liu, Bo, Stuhr, Uwe, Deng, Guochu, Stamp, Anton P. J., Zhao, Lin, Zhou, Xingjiang, Li, Shiliang, Pokhriyal, Amit, Ghosh, Haranath, Hong, Wenshan, Luo, Huiqian
Natura: Preprint
Pubblicazione: 2025
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author Li, Yang
Wu, Dingsong
Shu, Yingjie
Liu, Bo
Stuhr, Uwe
Deng, Guochu
Stamp, Anton P. J.
Zhao, Lin
Zhou, Xingjiang
Li, Shiliang
Pokhriyal, Amit
Ghosh, Haranath
Hong, Wenshan
Luo, Huiqian
author_facet Li, Yang
Wu, Dingsong
Shu, Yingjie
Liu, Bo
Stuhr, Uwe
Deng, Guochu
Stamp, Anton P. J.
Zhao, Lin
Zhou, Xingjiang
Li, Shiliang
Pokhriyal, Amit
Ghosh, Haranath
Hong, Wenshan
Luo, Huiqian
contents Elucidating the relationship between spin excitations and fermiology is essential for clarifying the pairing mechanism in iron-based superconductors (FeSCs). Here, we report inelastic neutron scattering results on the hole overdoped Ba$_{0.4}$K$_{0.6}$Fe$_2$As$_2$ near a Lifshitz transition, where the electron pocket at $M$ point is nearly replace by four hole pockets. In the normal state, the spin excitations are observed at incommensurate wave vectors with chimney-like dispersions. By cooling down to the superconducting state, a neutron spin resonance mode emerges with a peak energy of $E_r=$ 14-15 meV weakly modulated along $L$-direction. The incommensurability notably increases at low energies, giving rise to downward dispersions of the resonance mode. This behavior contrasts sharply with the upward dispersions of resonance observed in optimally doped Ba$_{0.67}$K$_{0.33}$Fe$_2$As$_2$ contributed by the hole to electron scattering, but resembles with the cases in KFe$_2$As$_2$ and KCa$_2$Fe$_4$As$_4$F$_2$ where the fermiology are dominated by hole pockets. These results highlight the critical role of electronic structure modifications near the Fermi level, especially in governing interband scattering under imperfect nesting conditions, which fundamentally shape the spin dynamics of FeSCs.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11000
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba$_{0.4}$K$_{0.6}$Fe$_2$As$_2$
Li, Yang
Wu, Dingsong
Shu, Yingjie
Liu, Bo
Stuhr, Uwe
Deng, Guochu
Stamp, Anton P. J.
Zhao, Lin
Zhou, Xingjiang
Li, Shiliang
Pokhriyal, Amit
Ghosh, Haranath
Hong, Wenshan
Luo, Huiqian
Superconductivity
Materials Science
Strongly Correlated Electrons
Elucidating the relationship between spin excitations and fermiology is essential for clarifying the pairing mechanism in iron-based superconductors (FeSCs). Here, we report inelastic neutron scattering results on the hole overdoped Ba$_{0.4}$K$_{0.6}$Fe$_2$As$_2$ near a Lifshitz transition, where the electron pocket at $M$ point is nearly replace by four hole pockets. In the normal state, the spin excitations are observed at incommensurate wave vectors with chimney-like dispersions. By cooling down to the superconducting state, a neutron spin resonance mode emerges with a peak energy of $E_r=$ 14-15 meV weakly modulated along $L$-direction. The incommensurability notably increases at low energies, giving rise to downward dispersions of the resonance mode. This behavior contrasts sharply with the upward dispersions of resonance observed in optimally doped Ba$_{0.67}$K$_{0.33}$Fe$_2$As$_2$ contributed by the hole to electron scattering, but resembles with the cases in KFe$_2$As$_2$ and KCa$_2$Fe$_4$As$_4$F$_2$ where the fermiology are dominated by hole pockets. These results highlight the critical role of electronic structure modifications near the Fermi level, especially in governing interband scattering under imperfect nesting conditions, which fundamentally shape the spin dynamics of FeSCs.
title Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba$_{0.4}$K$_{0.6}$Fe$_2$As$_2$
topic Superconductivity
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2505.11000